Full text of "Anthrax"
UNIVERSITY OF CALIFORNIA Agricultural experiment Station
College of Agriculture e. w. hilgard. director
CIRCULAR No. 4.
By ARCHIBALD R. WARD,
Veterinarian and Bacteriologist.
Synonyms. — Anthrax is also known by the following names: Charbon,
Splenic fever, Splenic apoplexy, Malignant carbuncle, Malignant pus-
tule, Woolsorters' disease.
Animals Affected. — The disease attracts attention chiefly as a cattle
disease, but it may be contracted by man and most of the domestic
animals, such as horses, sheep, swine, and dogs.
Conditions Under Which the Disease is Liable to Break Out. — Anthrax
is caused by the presence of bacteria in the blood, which generally gain
access to the body from the soil with the food. Anthrax germs thrive
and exist indefinitely in damp, heavy, undrained swampy land having a
high water-table or subject to periodical flooding. River-bottom land,
dried lake basins, or deltas are characteristic of the localities infected with
anthrax. The disease is most apt to occur during hot, dry weather.
At such times cattle are frequently pastured upon low lands which may
not be desirable nor available for use in the winter. In Louisiana the
disease is spread by the bite of large flies, causing swellings and sores
on the skin.
Symptoms. — The disease kills very quickly, sometimes in only a few
hours after sickness is noticed. There is high fever with the accom-
panying quickened breathing, hot horns and ears. Great variation in
behavior is noted in different affected animals. Sometimes there is
nervous excitement; sometimes great depression. The urine may be
dark and the dung may be bloody or streaked with blood. The nostrils,
tongue, etc., may be darkened in color. In some cases the disease affects
the skin, producing swellings that do not crackle when touched.
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Pigs affected by eating infected meat generally contract the disease
in the throat and intestines. There is marked swelling of the throat,
interfering with breathing; diarrhea and a darkened color of the tongue.
In man the disease occurs first as a malignant carbuncle, generally
traced to some slight wound, incurred while skinning an infected
carcass. Later there may be great swelling of the affected part, with
possible fatal termination.
Post-Mortem Appearances. — The blood is usually dark in color and
tarry in consistency. The spleen (milt) is always distended with a
bloody, pulpy mass. There is frequently found under the skin, and
around some of the internal organs, a gelatinous, yellowish, transparent
substance, which may be streaked with blood. It is exceedingly dan-
gerous to tamper with the carcass of an animal dead of anthrax, unless
the hands are protected by rubber gloves.
Disposal of the Dead. — Burning is the most desirable means of dis-
posal. If burial is necessary it is exceedingly desirable that the carcasses
of animals dead of anthrax be buried without being open to the air for
any length of time. A spot should be selected in a locality where there
is no danger of contaminating a stream of water. Animals grazing over
the grave, years after burial, are liable to contract the disease. Sur-
rounding the carcass with lime is desirable. Hogs will die if fed with
the carcasses of animals dead of anthrax.
Differences Between Anthrax and Texas Fever. — To the untrained
observer there are some similarities in the symptoms and internal
alterations of Texas fever and anthrax, and in consequence some con-
fusion exists. In both cases there is fever and there may be dark-colored
urine. In both the spleen is enlarged. Here the identity ceases.
Below are tabulated some of the more prominent differences between
them (From Law, Veterinary Medicine, Vol. 4):
Not restricted to swampy lands only.
Attacks bovine animals only.
Sucking calves nearly immune.
Mucosae become increasingly pale ; yellow
in violent attacks.
Blood becomes increasingly tbin and watery.
Bile abundant, tbick and tarry.
Prevails in ricb, swampy, impermeable
soils ; not permanently implanted on
open, well-drained land.
Attacks mammals, generally, especially
Sucking calves susceptible.
Mucosae dusky brownisb red ; not pallid nor
Blood becomes tbick, tarry, not watery.
It is an unfortunate fact that information concerning Texas fever has
not been sufficiently disseminated among stockmen, which has resulted
in undesirable confusion. The present writer holds the belief that
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many cases of Texas fever in the past have been called anthrax, and
that future investigations will show the regions infected with anthrax to
be much more restricted than is now generally believed to be the case.
Vaccination for Anthrax. — There is on the market a vaccine by which
it is claimed a mild attack of anthrax may be induced, with the result
that the animal is protected from a natural attack. Its use is much more
dangerous than the common practice of vaccinating for blackleg, and
vaccination for anthrax should be practiced only with great caution.
There is need of its use only upon animals actually pastured upon
swampy lands, which are known beyond a doubt to be infected with
anthrax. Do not vaccinate for anthrax merely because its outbreak is
dreaded, for some risk of actually introducing the disease is incurred
thereby. Anthrax originates in animals pastured on low, swampy land
and is not usually immediately communicated to other animals from
them unless there are carbuncles present on the surface of the body.
Animals may contract the disease on infected ground, and the disease
break out after they have been driven elsewhere and mixed with other
cattle, without the others contracting the disease.
Anthrax is an entirely different disease from blackleg, and conse-
quently blackleg vaccine is useless for preventing anthrax, and vice versa.
Treatment Unsatisfactory. — Anthrax does not usually yield to medici-
W. SHANNON, • - SUPT. STATE PRINTING.